(Tcl) Async SFTP Progress Info

Demonstrates checking for progress info updates when running a task asynchronously. This example demonstrates an SFTP download.

Chilkat Tcl Extension Downloads Chilkat Tcl Extension Downloads

load ./chilkat.dll

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

set sftp [new_CkSFtp]

# Set some timeouts, in milliseconds:
CkSFtp_put_ConnectTimeoutMs $sftp 15000
CkSFtp_put_IdleTimeoutMs $sftp 15000

# Connect to the SFTP server.  
set success [CkSFtp_Connect $sftp "sftp.example.com" 22]
if {$success != 1} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

# Authenticate with the SSH server.  Chilkat SFTP supports
# both password-based authenication as well as public-key
# authentication.  This example uses password authenication.
set success [CkSFtp_AuthenticatePw $sftp "myLogin" "myPassword"]
if {$success != 1} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

# After authenticating, the SFTP subsystem must be initialized:
set success [CkSFtp_InitializeSftp $sftp]
if {$success != 1} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

# --------------------
# Download a file
# --------------------
set localFilePath "c:/temp/hamlet.xml"
set remoteFilePath "subdir1/subdir2/hamlet.xml"

# Call the async version of the DownloadFileByName method to return a task object.
# The task object is loaded, but is in the Inert state -- meaning it is
# not yet scheduled to run on Chilkat's background thread pool.
# task is a CkTask
set task [CkSFtp_DownloadFileByNameAsync $sftp $remoteFilePath $localFilePath]
if {[CkSFtp_get_LastMethodSuccess $sftp] == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

# Before starting the task, tell it to keep an in-memory log of what would've been
# ProgressInfo callbacks.
CkTask_put_KeepProgressLog $task 1

# Schedule the task for running on the thread pool.  This changes the task's state
# from Inert to Live.
set success [CkTask_Run $task]
if {$success != 1} then {
    puts [CkTask_lastErrorText $task]
    delete_CkTask $task

    delete_CkSFtp $sftp
    exit
}

# The application is now free to do anything else
# while the file is being downloaded.

# For this example, we'll simply sleep and periodically
# check to see if the download is finished, and report the progress
# along the way.
set curPctDone 0

while {[CkTask_get_Finished $task] != 1} {

    if {[CkTask_get_PercentDone $task] != $curPctDone} then {
        set curPctDone [CkTask_get_PercentDone $task]
        puts "$curPctDone percent done"
    }

    # Check the progress info log.
    # Emit any log entries..
    while {[CkTask_get_ProgressLogSize $task] > 0} {
        # Get the 1st entry, emit it, and then remove it..
        set name [CkTask_progressInfoName $task 0]
        set value [CkTask_progressInfoValue $task 0]

        # Entries reporting the received byte count will have the name "RcvByteCount"
        # Entries reporting the current bytes-per-second will have the name "RcvBytesPerSec"

        puts "$name: $value"
        CkTask_RemoveProgressInfo $task 0
    }

    # Sleep 100 ms.
    CkTask_SleepMs $task 100

}

# Just in case there are any remaining entries...
while {[CkTask_get_ProgressLogSize $task] > 0} {
    # Get the 1st entry, emit it, and then remove it..
    set name [CkTask_progressInfoName $task 0]
    set value [CkTask_progressInfoValue $task 0]
    puts "$name: $value"
    CkTask_RemoveProgressInfo $task 0
}

# A finished task could be one that was canceled, aborted, or truly finished.  

# If the task was "canceled", it was canceled prior to actually starting.  This could
# happen if the task was canceled while waiting in a thread pool queue to be scheduled by Chilkat's
# background thread pool scheduler.  

# If the task was "aborted", it indicates that it was canceled while running in a background thread.  
# The ResultErrorText will likely indicate that the task was aborted.

# If the task "completed", then it ran to completion, but the actual success/failure of the method
# is determined by the result obtained via a GetResult* method.  (A "completed" task will
# have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
# been aborted or canceled:
if {[CkTask_get_StatusInt $task] != 7} then {
    puts "Task did not complete."
    puts "task status: [CkTask_status $task]"
    delete_CkTask $task

    delete_CkSFtp $sftp
    exit
}

# The DownloadFileByName method returns a boolean.  Therefore, after the task is finished,
# we can get the boolean result by calling GetResultBool.  This is the return value had
# we called DownloadFileByName synchronously.
set success [CkTask_GetResultBool $task]
if {$success != 1} then {
    # The task's ResultErrorText contains what would have been in the LastErrorText property had
    # the DownloadFileByName method been called synchronously.
    puts [CkTask_resultErrorText $task]
} else {
    puts "File downloaded asynchronously."
}

delete_CkTask $task


delete_CkSFtp $sftp